1. Field of the Invention
The invention is in the field of fluid sample acquisition and testing. In particular, the invention is directed to an apparatus useful for acquisition of a blood sample from a site on a subject's body and testing the blood glucose content of the blood sample utilizing a test strip. The strip may be incorporated into a device adapted for both sampling and sensing in a single step. Methods of using the apparatus are also disclosed.
2. Description of the Related Art
Self monitoring of blood glucose generally requires the user to extract a volume of capillary blood and place it on a disposable element for analysis.
Devices for lancing a subject at an extraction site to obtain a small quantity of blood for testing on a test strip are known in the prior art. For example, U.S. Pat. No. 6,558,402 B1, which is hereby incorporated by reference, discloses a lancer having suitable mechanisms for piercing a subject's skin and obtaining a sample.
Generally, once an incision is made, the extraction site must be “milked” to express fluid from the site, and the fluid must then be transferred to a strip. The trend in test strip devices is toward using ever smaller sample volumes to obtain a measurement. However, even as the sample volume required to obtain a measurement has fallen to the sub-microliter range, it is still generally necessary to express the fluid from the extraction site and transfer the sample to the test strip. Devices and techniques for expressing blood from an incision made by a lancer are disclosed in the prior art, for example in U.S. Pat. Nos. 6,793,633 B2, 6,071,251, and 6,752,817 B2, which are incorporated by reference.
Test strip sensing elements using amperometric and other techniques for determining the concentration of blood glucose in a blood sample are known in the prior art. U.S. Pat. Nos. 6,258,229 B1, 6,143,164 and 5,437,999, incorporated by reference herein, each disclose examples of test strip construction for electrochemical measurement of blood glucose.
An integrated lancet/sensor is disclosed in U.S. Patent Application Publication No. U.S. 2004/0064068, incorporated herein by reference. However, it would be desirable, and would represent an advance over the current state of the art, to provide a more convenient apparatus to obtain a blood sample from an extraction site on a subject, express the blood from the site, and to transport the sample to a measurement site on a test strip without complicated interaction required from the user.